Spatiotemporal characterization of zonal flows with multi-channel correlation Doppler reflectometers in the HL-2A Tokamak. (4th September 2015)

• Record Type: Journal Article
• Authors: Zhong, W.L.; Shi, Z.B.; Xu, Y.; Zou, X.L.; Duan, X.R.; Chen, W.; Jiang, M.; Yang, Z.C.; Zhang, B.Y.; Shi, P.W.; Liu, Z.T.; Xu, M.; Song, X.M.; Cheng, J.; Ke, R.; Nie, L.; Cui, Z.Y.; Fu, B.Z.; Ding, X.T.; Dong, J.Q.; Liu, Yi; Yan, L.W.; Yang, Q.W.; Liu, Y.
• Other Names: collab.
• Is Part Of: Nuclear fusion. Volume 55:Number 11(2015:Nov.)
• Publication Date: 2015-09-04
• Subjects: turbulence -- zonal flows -- Doppler reflectometry -- long-range correlation; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/0029-5515/55/11/113005
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: The oscillations of poloidal plasma flows induced by radially sheared zonal flows are investigated by newly developed correlation Doppler reflectometers in the HL-2A tokamak. The non-disturbing diagnostic allows one to routinely measure the rotation velocity of turbulence, and hence the radial electric field fluctuations. With correlation Doppler reflectometers, a three-dimensional spatial structure of geodesic acoustic mode (GAM) is surveyed, including the symmetric feature of poloidal and toroidal E r fluctuations, the dependence of GAM frequency on radial temperature and the radial propagation of GAMs. The co-existence of low-frequency zonal flow and GAM is presented. The temporal behaviors of GAM during ramp-up experiments of plasma current and electron density are studied, which reveal the underlying damping mechanisms for the GAM oscillation level.